Inland Fisheries Ireland (IFI) is carrying out an investigation into a fish kill at Curraghalicky Lake near Dunmanway.
It is one of three separate investigations being undertaken by the state body in Cork and Kerry.
Several hundred juvenile bream were recovered from Curraghalicky Lake today.
'IFI works with other government agencies in line with the new national interagency protocol for investigating significant fish kills - and the protocol has now been now activated in relation to this incident,' said a IFI spokesperson.
'Relevant agencies have been notified including the Environmental Protection Agency (EPA), Cork County Council, the Marine Institute, and the River Basin Management Service.
The two other investigations relate to suspected pollution in the Ross River in Killavullen in North Cork and in the Deenagh Rier in Killarney, County Kerry.
Monitoring and assessment of the impacts at all three sites will continue to be undertaken.
IFI continues to urge the public to report issues of concern to its confidential 24/7 number, 0818 34 74 24.
